Children with Developmental Apraxia of Speech Communication Profiles and Interventions

1. Children with Developmental Apraxia of SpeechCommunication Profiles and Interventions Laura J. Ball, Ph. D. Munroe-Meyer Institute for Genetics and Rehabilitation University of Nebraska Medical Center, Omaha

2. Demographics • Onset • Course • Gender • Prevalence • Aggregation

3. Research Classifications Unitary Entity: isolate one characteristic that differentiates DAS from other childhood speech problems. Syndrome does not require one “necessary and sufficient” dx criterion. Subtypes:behavioral characteristics are associated with dx criteria for each of 2+ subtypes of the disorder.

4. Theoretical Perspective • Shriberg et.al., (1997a, 97b, 97c) present a schema for speech production in DAS with linguistic processing stages. 1. Input processes (auditory-temporal, perceptual) 2. Organizational processes ( representational, transformational) 3. Output processes (selection-retrieval, pre-articulatory sequencing) 4. Articulatory execution.

5. DAS: Deficit in Input Processes? Auditory-Temporal & Perceptual input processes are usually proposed from 2 general perspectives. Children with DAS have: 1. Across-the-board deficits in language processes. 2. Specific deficits in either formulation or transformation of appropriate phonological representations.

6. Robin et.al., (1993) noted that children had disordered prosody, suggesting that “impaired temporal perception could impact ability to gain information about durational aspects of prosody and add to the observed prosodic difficulties.”

7. DAS: Deficit in Organizational Processes? Representational & Perceptual Organization Velleman & Strand (1994) implicate representational processing. They suggest that children with DAS “could be seen as impaired in their ability to generate & utilize frames, which would otherwise provide the mechanisms for analyzing, organizing, & utilizing information from their motor, sensory, & linguistic systems for the production of spoken language.”

8. Maassen, Thoonen, & Gabreels (1993): Children with DAS demonstrate a “phonological encoding disorder.”

9. Snow, Marquardt, & Davis (1992): Children with DAS “demonstrate an apparent breakdown in the ability to perceive ‘syllableness’ and access & compare syllable representations with regard to position & structure.”

10. Groenen, Crul, Maassen, & Thoonen (1993): “weaker auditory memory traces” suggest perceptual discrimination tasks have diagnostic value. “The degree of dysfunction in speech production is related to the degree of dysfunction in speech perception.”

11. Transformational Organization • Morphophonemic, allophonic & sociolinguistic rules appear to be intact.

12. DAS: Deficit in Output Processes? Pre-articulatory Sequencing • (most prevalent) attributes the variability observed in speech output to deficits in pre-articulatory sequencing of the spatio-temporal movements for speech sounds.

13. Selection-Retrieval • Phonetic variability involves a lower-level deficit in motor programming, rather than retrieval of phonemic units. • Walton & Pollack (1991) “motor theory”: “Although one could argue that there is a phonemic confusion in the speech of these children, one could also argue that their ability to demonstrate these contrasts is lost when their motor systems are taxed or challenged.”

14. DAS is a disorder of movement

15. Diagnostic Features Speech Errors: • Differ from errors of children with developmental delay, phonological processes. • Resemble errors of adult acquired apraxia (contrast between voluntary and involuntary performance, variability of errors). • Differ from dysarthria, which has errors in phonation, resonance, articulation & prosody.

16. DAS impacts all aspects of communication

17. Why do we Communicate? Light (1988) identified four purposes of social communication: 1. expression of wants or needs, 2. transfer of information, 3. social closeness, and 4. social etiquette.

18. Important Aspects 1. DAS as a disorder of movement 2. DAS as a disorder impacting all aspects of communication

19. DAS Defined Typically defined in terms of sound production error patterns, actually a disorder of movement. Difficulty is noted with purposeful voluntary movements for speech, creating an inability to sequence speech movements in the absence of paralysis.

20. DAS is a disorder of movement

21. Survey of SLPs Participants • regional SLP’s treating DAS Profiles • children actually in treatment Perspective • clinical awareness vs. “pure” research version

22. Profiles

23. DAS & Communication: Characteristics Decreased intelligibility Disordered language Social withdrawal Behavioral aggression Academic failure

24. Important Aspects…gee, notice a pattern here? 1. DAS as a disorder of movement 2. DAS as a disorder impacting all aspects of communication

25. Screening for DAS • Address increase in referrals & diagnoses of DAS among preschool population • Short administration time • Organize, streamline assessment process • Increase assessment efficiency • Morehouse & Linderman, 2000

26. Screening for Developmental Apraxia of Speech (SDAS) • Oral Motor Movements • Phoneme Stimulability • Intelligibility • Checklist of DAS Characteristics • Increasing Word Length • Multisyllabic Words Across Trials • Interpretation & Recommendations • Morehouse & Linderman, 2000

27. Assessment of DAS(Strand, 1998) Neuromuscular Muscle strength, tone, & coordination Reflexes Sensory function Structural Function Structures, tissue characteristics, & sensation Range of motion, strength, coordination, speed, & ability to vary muscle tension.

28. Motor Speech Production Simple to complex phonetic sequencing: • CV, VC, CVC (vary the vowel) • monosyllabic words • multisyllabic words • phrases • sentences of increasing length

29. Assess at Level of Breakdown Examine any vowels NOT heard in spontaneous speech Examine CV/VC combinations, also omitting those heard in spontaneous speech Examine CVC productions, omitting those heard in spontaneous speech • same 1st & last phoneme • different 1st & last phoneme

30. Examine Words of Increasing Length • simultaneous production with examiner • direct imitation • delayed imitation

31. Examine Multisyllabic Words • simultaneous production with examiner • direct imitation • delayed imitation

32. Physiological functioning for speech production • Respiration • Laryngeal function • Resonance: Large number • hyper- nasal • hypo- nasal • mixed nasality

33. Articulation & Phonology • What evaluation procedures would be most appropriate to address the needs of children with DAS? • What evaluation procedures would be most appropriate to address the needs of children with motor-based speech disorders?

34. Intelligibility & Comprehensibility • What are the most appropriate means of assessing intelligibility in young children? • How might you get a measure of a child’s comprehensibility vs. intelligibility?

35. Intelligibility/Comprehensibility Index of Augmented Speech Comprehensibility in Children (I-ASCC) (Dowden, 1997) A non-standardized clinical measure to assess comprehensibility.

36. I-ASCC Hierarchy Present a picture with a verbal cue such as “What is this?” Present a picture and provide contextual cues such as “It’s a food you might eat. What is it?” Present a picture plus an embedded model such as “It’s pizza. Now you say it.”

38. Intelligibility Judge listens to taped utterances without contextual cues and transcribes.

39. Comprehensibility After listening to & judging the entire set of utterances without contextual cues, the listener rewinds the tape, reads a contextual cue and transcribes again.

40. Contextual Cues • Something children eat at snack time. • Something children use during craft time. • Something children eat for lunch. • Clothing young girls wear outside. • What you see children doing with a book.

41. Language • What current methods exist to measure expressive language in unintelligible children? • What are the most appropriate assessment procedures for assessing both receptive and expressive language in children with DAS?

42. Clinically, consider of ALL of the following: Movement skills Receptive & expressive language skills Physical structures and functions Comprehensibility Communication repertoires in use

43. Differential Diagnosis Determine which characteristics are most readily apparent. Are there dominant speech characteristics? • Dysarthria vs. DAS • Fluency disorder vs. DAS • Phonological disorder vs. DAS • Developmental articulation vs. DAS

44. Research Questions What attributes of overall communication disabilities are found in children with DAS? Do clusters based on communication disabilities exist for children with DAS?

45. Methods N=36 children with DAS Screening: • DAS Screening Instrument(Blakeley, 1980) • Child Social Interaction Scales(Adapted from Booth-Butterfield and Gould, 1986; Duran, 1992; Wiemann, 1977; Canary and Spitzberg, 1987; McCrosky, 1982; Christophel, 1990; and Burgoon, 1976.)

46. Criteria for Inclusion • Committee of 3 DAS experts rated “degree of DAS” • A mean score  3, considered DAS

47. Articulation and Phonology Do children with DAS use phonological processes? Examine consistency of productions. • Khan-Lewis Phonological Analysis Articulation & prosody • Goldman-Fristoe Test of Articulation • Consider impact on language skills & reading development

48. Language • Language sample if intelligibility allows • Comprehensive receptive & expressive • Morphology & syntax • Test of Auditory Comprehension of Language (III) (1998) • Peabody Picture Vocabulary Test (IIIA/B)

49. Communication Social communication skills Behavioral communication repertoires Academic communication skills • Social Skills Rating System (Gresham and Elliott, 1990)

50. Assessment Procedures Contributing to DAS Profile Identification